package com.neuresys.database.databaseimpl.jssqlite;

public class Base64Coder {

	// Mapping table from 6-bit nibbles to Base64 characters.
	private static char[] map1 = new char[64];
	static {
	int i=0;
	for (char c='A'; c<='Z'; c++) map1[i++] = c;
	for (char c='a'; c<='z'; c++) map1[i++] = c;
	for (char c='0'; c<='9'; c++) map1[i++] = c;
	map1[i++] = '+'; map1[i++] = '/'; }

	// Mapping table from Base64 characters to 6-bit nibbles.
	private static byte[] map2 = new byte[128];
	static {
	for (int i=0; i<map2.length; i++) map2[i] = -1;
	for (int i=0; i<64; i++) map2[map1[i]] = (byte)i; }

	/**
	* Encodes a string into Base64 format.
	* No blanks or line breaks are inserted.
	* @param s a String to be encoded.
	* @return A String with the Base64 encoded data.
	*/
	public static String encodeString (String s) {
	return new String(encode(s.getBytes())); }

	/**
	* Encodes a byte array into Base64 format.
	* No blanks or line breaks are inserted.
	* @param in an array containing the data bytes to be encoded.
	* @return A character array with the Base64 encoded data.
	*/
	public static char[] encode (byte[] in) {
	return encode(in,in.length); }

	/**
	* Encodes a byte array into Base64 format.
	* No blanks or line breaks are inserted.
	* @param in an array containing the data bytes to be encoded.
	* @param iLen number of bytes to process in <code>in</code>.
	* @return A character array with the Base64 encoded data.
	*/
	public static char[] encode (byte[] in, int iLen) {
	int oDataLen = (iLen*4+2)/3; // output length without padding
	int oLen = ((iLen+2)/3)*4; // output length including padding
	char[] out = new char[oLen];
	int ip = 0;
	int op = 0;
	while (ip < iLen) {
	int i0 = in[ip++] & 0xff;
	int i1 = ip < iLen ? in[ip++] & 0xff : 0;
	int i2 = ip < iLen ? in[ip++] & 0xff : 0;
	int o0 = i0 >>> 2;
	int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
	int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
	int o3 = i2 & 0x3F;
	out[op++] = map1[o0];
	out[op++] = map1[o1];
	out[op] = op < oDataLen ? map1[o2] : '='; op++;
	out[op] = op < oDataLen ? map1[o3] : '='; op++; }
	return out; }

	/**
	* Decodes a string from Base64 format.
	* @param s a Base64 String to be decoded.
	* @return A String containing the decoded data.
	* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
	*/
	public static String decodeString (String s) {
	return new String(decode(s)); }

	/**
	* Decodes a byte array from Base64 format.
	* @param s a Base64 String to be decoded.
	* @return An array containing the decoded data bytes.
	* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
	*/
	public static byte[] decode (String s) {
	return decode(s.toCharArray()); }

	/**
	* Decodes a byte array from Base64 format.
	* No blanks or line breaks are allowed within the Base64 encoded data.
	* @param in a character array containing the Base64 encoded data.
	* @return An array containing the decoded data bytes.
	* @throws IllegalArgumentException if the input is not valid Base64 encoded data.
	*/
	public static byte[] decode (char[] in) {
	int iLen = in.length;
	if (iLen%4 != 0) throw new IllegalArgumentException ("Length of Base64 encoded input string is not a multiple of 4.");
	while (iLen > 0 && in[iLen-1] == '=') iLen--;
	int oLen = (iLen*3) / 4;
	byte[] out = new byte[oLen];
	int ip = 0;
	int op = 0;
	while (ip < iLen) {
	int i0 = in[ip++];
	int i1 = in[ip++];
	int i2 = ip < iLen ? in[ip++] : 'A';
	int i3 = ip < iLen ? in[ip++] : 'A';
	if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
	throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
	int b0 = map2[i0];
	int b1 = map2[i1];
	int b2 = map2[i2];
	int b3 = map2[i3];
	if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
	throw new IllegalArgumentException ("Illegal character in Base64 encoded data.");
	int o0 = ( b0 <<2) | (b1>>>4);
	int o1 = ((b1 & 0xf)<<4) | (b2>>>2);
	int o2 = ((b2 & 3)<<6) | b3;
	out[op++] = (byte)o0;
	if (op<oLen) out[op++] = (byte)o1;
	if (op<oLen) out[op++] = (byte)o2; }
	return out; }

	// Dummy constructor.
	private Base64Coder() {}

	} // end class Base64Coder